1. Technical Field
The present invention relates to a feed device and a recording apparatus that perform a skew removal operation that removes skew (slant) of a medium in a process of feeding the medium.
2. Related Art
JP-A-2007-84224 discloses a recording apparatus provided with a feed device that has a skew removing function for a sheet (example of a medium). The recording apparatus is provided with a transport roller pair (example of a second roller) at a position further to the downstream side in the feeding direction than the feed roller (example of a first roller) in a process of feeding a sheet, and performs skew removal on the sheet by reversing the transport roller pair in a state where the feed roller is stopped after the leading edge of the sheet is delivered to the downstream side by a predetermined amount from the nip point of the transport roller pair. That is, a “biting operation” that delivers a predetermined amount of the leading edge of the sheet fed by the feed roller further to the downstream side than the nip point of the transport roller pair and, thereafter, a “discharging operation” in which the transport roller pair is reversed in a state where the feed roller is stopped are performed. Since the sheet is in a state of being nipped by the feed roller and a retard roller, the sheet, the leading edge of which is discharged to the upstream side, is bent between the feed roller and the transport roller pair, and the sheet leading is not at the nip point of the transport roller pair, that is, the sheet becomes parallel and skew is removed. In cases where the sheet is thick, because the feed roller is prevented from reversing when the discharging operation is performed, a braking unit (reversal prevention unit of the feed roller) is provided in the recording apparatus disclosed in JP-A-2007-84224.
A hopper is biased in a direction from the standby position towards the feeding position by an elastic member, and is inclined between the standby position and the feed position interlinked with the rotation of the rotation shaft of the feed roller by the power of the feed motor via engagement between a cam provided on the rotation shaft of the feed roller and a cam follower provided in the hopper.
Incidentally, due to causes such as a reduced diameter of the feed roller, slipperiness of the sheet in the feeding process, and variations in the feed start timing of the sheet, when the biasing force from the elastic member of the hopper acts on the rotation shaft in the process of the discharging operation performed with the feed motor in a stopped state, the feed roller reverses, and there are cases where skew removal is not appropriately performed. In the recording apparatus in JP-A-2007-84224, although a braking unit (feed roller reversal prevention unit) is provided for preventing the feed roller from reversing with the stiffness of a sheet formed from a thick sheet, there is a problem in that providing the braking unit prevents size reductions in the feed device and the printer, and the structure of the device becomes complicated.
This type of problem is not limited to the biasing force of the elastic member that biases the hopper being the cause, and in a configuration that performs skew removal by reverse transporting a medium with a second roller, it is similarly difficult to appropriately perform the skew removal even in cases where the first roller is excessively reversed by any external force.